Challenges and trends in apomorphine drug delivery systems for the treatment of Parkinson's disease

Parkinson's disease(PD) is a chronic debilitating disease affecting approximately 1% of the population over the age of 60. The severity of PD is correlated to the degree of dopaminergic neuronal loss. Apomorphine has a similar chemical structure as the neurotransmitter dopamine and has been used for the treatment of advanced PD patients. In PD patients,apomorphine is normally administered subcutaneously with frequent injections because of the compound's extensive hepatic first-pass metabolism. There is, hence, a large unmet need for alternative administrative routes for apomorphine to improve patient compliance.The present review focuses on the research and development of alternative delivery of apomorphine, aiming to highlight the potential of non-invasive apomorphine therapy in PD,such as sublingual delivery and transdermal delivery.

Repression of oxidative stress/reactive metabolite regulated gene expression is associated with conversion of carbamazepine into a hepatotoxicant in LPS and DSS rat models

Idiosyncratic hepatotoxicity accounts for many drug failures in the clinic and is a leading cause for black-boxed and withdrawn drugs. This toxicity has proven difficult to predict preclinically, but correlates with oxidative stress/reactive metabolites (OS/RM). As noted previously for antiepileptic compounds, many drugs causing idiosyncratic adverse drug effects are detected by OS/RM gene expression responses in the rat. In the present study, two immune activation models, low dose lipopolysaccharide (1 mg/kg IV) and 5% dextran sulphate sodium (DSS) in drinking water, were examined to determine if either would convert the non-toxic idiosyncratic toxicant carbamazepine (225 mg/kg) into a rat hepatotoxicant at 24 hours. Using the low dose LPS model, about 1/3 of the carbamazepine-treated rats either showed robust ALT and AST elevations with histopathological evidence of hepatotoxicity, or died. Rats in this LPS/carbamazepine group were subdivided based on ALT values into non-responders, responders or robust responders. Whereas most carbamazepine-induced mRNAs were repressed by LPS across all rats in this group, the OS/ RM genes aflatoxin aldehyde reductase (Afar) and glutathione transferase Ya (Gstya) were repressed only in the robust responder subgroup;it is unclear whether repression of these genes contributes to or results from hepatotoxicity. The OS/RM gene microsomal epoxide hydrolase (mEphx) showed repression across all rats. NAD(P)H: menadione oxidoreductase (Nmor) is an OS/RM-responsive gene that is also induced by LPS, confounding interpretation of its changes. After pretreatment with 5% DSS at 24 hours or for 5 days, using a protocol that reportedly produces increased endotoxin absorption, carbamazepine was not converted to a hepatototoxicant in any rats. Instead, DSS produced a pronounced (2- to 6-fold) and selective potentiation of carbamazepine induction of OS/RM-responsive mRNAs. The lack of repressive effects of DSS on these mRNAs or in converting carbamazepine to a hepatotoxicant was not due to desensitization of endotoxin responses since LPS was at least as effective when administered to DSS-pretreated rats. OS/RM gene repression may contribute to development of hepatotoxicity of carbamazepine in immune activation models.

An Open-label, Self-control, Prospective Study on Cognitive Function, Academic Performance, and Tolerability of Osmotic-release Oral System Methylphenidate in Children with Attention-deficit Hyperactivity Disorder

Background： Attention-deficit hyperactivity disorder （ADHD） is the most common mental and behavioral disorder in school-aged children. This study evaluated the effect of osmotic-release oral system （OROS） methylphenidate （MPH） on cognitive function and academic performance of Chinese school-aged children with ADHD. Methods： This 12-week, prospective, multicenter, open-label, self-controlled study enrolled 153 Chinese school-aged children with ADHD and 41 non-ADHD children. Children with ADHD were treated with once-daily OROS-MPH （18 mg, 36 mg, or 54 mg）. The primary endpoints were Inattention/Overactivity （I/O） with Aggression Conners Behavior Rating Scale （IOWA） and Digit Span Test at week 12 compared with baseline. Secondary endpoints included opposition/defiant （O/D） subscale of IOWA, Clinical Global Impression （CGI）, Coding Test, Stroop Color-word Test, Wisconsin Card Sorting Test （WCST）, academic performance on teacher-rated school examinations, and safety at week 12 compared with baseline. Both non-ADHD and ADHD children received the same frequency of cognitive operational test to avoid the possible bias caused by training. Results： A total of 128 patients were evaluated with cognitive assessments. The OROS-MPH treatment significantly improved IOWA Conners I/O subscale scores at week 12 （3.8 ± 2.3） versus baseline （10.0 ± 2.4; P 〈 0.0001）. Digit Span Test scores improved significantly （P 〈 0.0001 ） with a high remission rate （81.1%） at week 12 versus baseline. A significant （P 〈 0.0001 ） improvement was observed in O/D subscale of IOWA, CGI, Coding Test, Stroop Color-word Test, WCST, and academic performance at week 12 versus baseline. Very few practice-related improvements were noticed in the non-ADHD group at week 12 compared with baseline. No serious adverse events and deaths were reported during the study. Conclusions： The OROS-MPH treatment effectively controlled symptoms of ADHD and significantly improved academic performance and cognitive fimction of Chinese school-aged children with ADHD. The treatment was found to be sate and generally well-tolerated over 12 weeks.

Fundamental aspects of solid dispersion technology for poorly soluble drugs

The solid dispersion has become an established solubilization technology for poorly water soluble drugs.Since a solid dispersion is basically a drug-polymer two-component system,the drug-polymer interaction is the determining factor in its design and performance.In this review,we summarize our current understanding of solid dispersions both in the solid state and in dissolution,emphasizing the fundamental aspects of this important technology.

Apalutamide for patients with metastatic castrationsensitive prostate cancer in East Asia:a subgroup analysis of the TITAN trial

Ethnicity might be associated with treatment outcomes in advanced prostate cancer.This study aimed to evaluate the efficacy and safety of androgen deprivation therapy(ADT)combined with apalutamide in East Asians with metastatic castration-sensitive prostate cancer(mCSPC).The original phase 3 Targeted Investigational Treatment Analysis of Novel Anti-androgen(TITAN)trial was conducted at 260 sites in 23 countries.This subgroup analysis included patients enrolled in 62 participating centers in China,Japan,and Korea.Radiographic progression-free survival(PFS),time to prostate-specific antigen(PSA)progression,and PSA changes from baseline were compared between groups in the East Asian population.The intent-to-treat East Asian population included 111 and 110 participants in the apalutamide and placebo groups,respectively.The 24-month radiographic PFS rates were 76.1%and 52.3%in the apalutamide and placebo groups,respectively(apalutamide vs placebo:hazard ratio[HR]=0.506;95%confidence interval[CI],0.302–0.849;P=0.009).Median time to PSA progression was more favorable with apalutamide than placebo(HR=0.210;95%CI,0.124–0.357;P<0.001).Median maximum percentages of PSA decline from baseline were 99.0%and 73.9%in the apalutamide and placebo groups,respectively.The most common adverse event(AE)was rash in the apalutamide group,with a higher rate than that in the placebo group(37.3%vs 9.1%).The most common grade 3 or 4 AEs were rash(12[10.9%])and hypertension(12[10.9%])for apalutamide.The efficacy and safety of apalutamide in the East Asian subgroup of the TITAN trial are consistent with the global results.

Apalutamide for metastatic castration-sensitive prostate cancer:final analysis of the Asian subpopulation in the TITAN trial

The final analysis of the phase 3 Targeted Investigational Treatment Analysis of Novel Anti-androgen(TITAN)trial showed improvement in overall survival(OS)and other efficacy endpoints with apalutamide plus androgen deprivation therapy(ADT)versus ADT alone in patients with metastatic castration-sensitive prostate cancer(mCSPC).As ethnicity and regional differences may affect treatment outcomes in advanced prostate cancer,a post hoc final analysis was conducted to assess the efficacy and safety of apalutamide in the Asian subpopulation.Event-driven endpoints were OS,and time from randomization to initiation of castration resistance,prostate-specific antigen(PSA)progression,and second progression-free survival(PFS2)on first subsequent therapy or death.Efficacy endpoints were assessed using the Kaplan–Meier method and Cox proportional-hazards models without formal statistical testing and adjustment for multiplicity.Participating Asian patients received once-daily apalutamide 240 mg(n=111)or placebo(n=110)plus ADT.After a median follow-up of 42.5 months and despite crossover of 47 placebo recipients to open-label apalutamide,apalutamide reduced the risk of death by 32%(hazard ratio[HR]:0.68;95%confidence interval[CI]:0.42–1.13),risk of castration resistance by 69%(HR:0.31;95%CI:0.21–0.46),PSA progression by 79%(HR:0.21;95%CI:0.13–0.35)and PFS2 by 24%(HR:0.76;95%CI:0.44–1.29)relative to placebo.The outcomes were comparable between subgroups with low-and high-volume disease at baseline.No new safety issues were identified.Apalutamide provides valuable clinical benefits to Asian patients with mCSPC,with an efficacy and safety profile consistent with that in the overall patient population.